Self-slitting spectroscope

ABSTRACT

A self-slitting spectroscope comprising a narrow source along the axis of a hemi-cylindrical transmission grating of very large size to permit simultaneous viewing of spectral phenomena by a large number of observers.

[ 1 Aug. 29, 1972 United States Patent Steinhardt et al.

[54] SELF-SLITTING SPECTROSCOPE [72] Inventors: Ralph G. Steinhardt, Box9716, Hollins College, Va. 24020; Julia Cutting......................35/19 B W. Calhoun, 326 Melrose Lane,

8 m a n M .mwm wmm 2;. m R ,m r wms mmm mxB EMF n wmw sr inm nmm 2 n1 amc NB mm Q T m m m H U ABSTRACT [21] Appl. No.: 127,251

52 US. Cl......................................356/74, 35/19 B ASelf-slitting SPectroswpe comprising a "arrow 51 1111.3/00, 60% 23/06 f9 the axis of transmis- [58] Field ofSearch....................356/7479- 35/19 B large Permit slmulmews viewing of spectral phenomena by alarge number of observers.

9 Claims, 3 Drawing Figures SELF-SLITTING SPECTROSCOPE BACKGROUND OF THEINVENTION This invention relates to spectroscopy, and more particularlyto a very large spectroscope for simultaneous viewing by a large numberof observers.

The spectroscopes generally known comprise a source of electromagneticradiation in the visible range, a planar transmission grating of prism,and a mask with a very narrow aperture or slit disposed between thesource and the grating to restrict the irradiation of the transmissiongrating to the energy radiated through the slit. Such spectroscopes aregenerally quite small in size and restrict the viewing of spectralphenomena to one person.

Apparatus for demonstrating spectral phenomena simultaneously to largenumbers of viewers, e. g., a class of students, are generally smallindividual gratings used individually by the viewers. Since no twoviewers are observing the same grating, uncertainties are therebycreated as to whether or not the same spectral phenomena are present andbeing viewed by the different observers.

Another technique for demonstrating spectral phenomena simultaneously tolarge numbers of viewers involves the projection of radiation through anarrow slit and a prism or grating onto a wide screen. These techniquesrequire an extremely intense source and are generally limited to viewinga continuous spectrum.

It is accordingly an object of the present invention to provide novelapparatus for group viewing of spectral phenomena.

It is another object of the present invention to provide a novelapparatus for group viewing of spectral phenomena without the use ofprojection techniques.

It is still another object of the present invention to provide a novelspectral phenomena viewing apparatus utilizing a single largetransmission grating.

It is yet another object of the present invention to provide novelapparatus for viewing spectral phenomena with or without the use of aradiation filter disposed between the radiation source and thetransmission grating.

It is yet still another object of the present invention to provide novelapparatus for viewing spectral phenomena from a low intensity source.

It is yet still another object of the present invention to provide novelapparatus exceeding about one square foot in area for viewing spectralphenomena.

These and other objects and advantages of the present invention will bereadily apparent from the claims and from the following detaileddescription of a preferred embodiment when readin conjunction with theappended drawings.

THE DRAWINGS FIG. 1 is a pictorial view of one embodiment of the presentinvention with portions broken away to illustrate the constructionthereof;

FIG. 2 is a horizontal section taken through lines 2- 2ofFIG.1;and

FIG. 3 is a vertical section taken through lines 3--3 of FIG. 2.

THE PREFERRED EMBODIMENT With reference now to the drawings, thepreferred embodiment comprises a rigid housing which may be constructedout of wood or other suitable materials. The housing includes end walls10 and 12, a back wall 14 and a front wall 16. The back wall 14 may beprovided with a door 18 suitably hinged to the back wall 14 byconventional means (not shown) to provide access to the interior of thehousing. The front wall 16 of the housing may be apertured across theheight thereof to provide sufficient space for the mounting of a narrowsource 20 of electromagnetic radiation at a range of wavelengths fromabout 700 to about 400 nanometers. Suitable reinforcing members 21 maybe included as necessary to structurally reinforce the housing and toprovide the desired rigidity.

In the preferred embodiment illustrated, the source 20 comprises atungsten wire of approximately 0.1 to 4 millimeters in diameter, heatedelectrically to incandescence in vacuo or in an inert gas at suitablemounting plates 22 and 24 conveniently aligned with the front wall l6 ofthe housing in the center of the aperture therein and a suitable sourceof power (not shown) connected thereto. The mounting plates 22 and 24may be connected in any suitable convenient manner to the top 26 andbottom 28 surfaces of the housing which may extend, as illustrated, toprovide support for the transmission grating 30 hereinafter to bedescribed.

The transmission grating 30, as particularly illustrated in FIGS. 1 and3, may be of any suitable transparent material such as glass or plasticruled with parallel lines at a density of about 6,000 to about 20,000lines per inch. In this regard, the generally available density of13,400 lines per inch has been found generally satisfactory. The linesare parallel to the length of the wire 20 and the grating height may bein excess of about 6 inches. The transmission grating 30 may belaminated between suitable sheets 32 and 34 of transparent material suchas glass or plastic to provide additional support for the grating 30.Transparent material of a thickness of one-sixteenth inch has been foundsuitable for this purpose.

The transmission grating 30 is conveniently arranged in the form of ahemi-cylinder about the wire 20. By means of a grating of the typedescribed having a radius of approximately 18 inches and a height ofapproximately the same dimension, spectral phenomena in the visibleregion have been simultaneously demonstrated to large numbers of people.

The grating 30 need not, however, be of a constant radius or evenarcuate, as one or a series of planar surfaces may be successfullyutilized. If, however, the spectroscope is to be utilized to obtainquantitative data, the radius to the grating should be substantiallyconstant. The area of the grating should be in excess of about 1 squarefoot.

Other sources such as a Geissler or other gas discharge tube may beutilized in lieu of the tungsten wire or ribbon disclosed. The sourcemust, however, be narrow, i.e., self-slitting, in order to permitviewing of the spectral phenomena by large numbers of observers. Thenature of the source is not critical so long as the wavelength of theemitted energy lies in the range of about 700 to 400 nanometers, i.e.the visible range.

One or more optical filters (not shown) may be interposed between thesource and the grating 30, or between the grating and the viewer topermit demonstration of spectral absorption.

The present invention may thus be embodied in other specific formswithout departing from the spirit or essential characterization thereof.For example, a suitable scale may be provided on the constant radiusembodiment illustrated to facilitate obtaining quantitativespectroscopic data. The presently disclosed embodiments are therefore tobe considered in all respects as illustrative and not restrictive, thescope of the invention being indicated by the appended claims ratherthan by the foregoing description, and all changes which come' withinthe meaning and range of equivalency of the claims are thereforeintended to be embraced therein.

What is claimed is:

l. A self-slitting spectroscope for the simultaneous viewing of spectralphenomena in the visible region by a plurality of observers comprising:

a semi-cylindrical transmission grating, the area of said grating beingsufficient to permit the simultaneous viewing of the grating by aplurality of observers; and,

a self-slitting source of electromagnetic wave energy having awavelength in the range from about 700 to about 400 nanometers, saidsource being mounted on the axis of said transmission grating whereby aplurality of observers may simultaneously view spectral phenomena in thevisible region.

2. The self-slitting spectroscope of claim 1 wherein said grating islaminated between sheets of plastic.

3. The self-slitting spectroscope of claim 1 wherein said source is agas discharge tube.

4. The self-slitting spectroscope of claim 1 wherein said source is atungsten wire having a width less than about 10 millimeters.

5. The self-slitting spectroscope of claim 1 wherein the radius of saidgrating is not less than about 1 foot.

6. The self-slitting spectroscope of claim 5 wherein said grating islaminated between sheets of plastic; and

wherein said source is a tungsten wire having a diameter less than about10 millimeters.

7. The self-slitting spectroscope of claim 6 wherein the height of saidgrating is substantially equal to the radius thereof.

8. The self-slitting spectroscope of claim 1 wherein the height of saidgrating is substantially equal to the radius thereof.

9. A self-slitting spectroscope for the simultaneous viewing of spectralphenomena in the visible region by a plurality of persons comprising:

a housing having an elongated aperture in one wall thereof;

an elongated source of electromagnetic energy at a wavelength in therange from about 700 to 400 nanometers;

means for mounting saidsource in the aperture in said one wall of saidhousing;

a transmission grating including a transparent material having a heightof not less than about 6 inches, an area not less than about 1 squarefoot and being ruled with not less than about 6,000

lines to the inch; and means for mounting said transmission grating at adistance not less than about 1 foot from the aper ture in said one wallwhereby a plurality of observers may simultaneously view spectralphenomena in the visible region.

1. A self-slitting spectroscope for the simultaneous viewing of spectralphenomena in the visible region by a plurality of observers comprising:a semi-cylindrical transmission grating, the area of said grating beingsufficient to permit the simultaneous viewing of the grating by aplurality of observers; and, a self-slitting source of electromagneticwave energy having a wavelength in the range from about 700 to about 400nanometers, said source being mounted on the axis of said transmissiongrating whereby a plurality of observers may simultaneously viewspectral phenomena in the visible region.
 2. The self-slittingspectroscope of claim 1 wherein said grating is laminated between sheetsof plastic.
 3. The self-slitting spectroscope of claim 1 wherein saidsource is a gas discharge tube.
 4. The self-slitting spectroscope ofclaim 1 wherein said source is a tungsten wire having a width less thanabout 10 millimeters.
 5. The self-slitting spectroscope of claim 1wherein the radius of said grating is not less than about 1 foot.
 6. Theself-slitting spectroscope of claim 5 wherein said grating is laminatedbetween sheets of plastic; and wherein said source is a tungsten wirehaving a diameter less than about 10 millimeters.
 7. The self-slittingspectroscope of claim 6 wherein the height of said grating issubstantially equal to the radius thereof.
 8. The self-slittingspectroscope of claim 1 wherein the height of said grating issubstantially equal to the radius thereof.
 9. A self-slittingspectroscope for the simultaneous viewing of spectral phenomena in thevisible region by a plurality of persons comprising: a housing having anelongated aperture in one wall thereof; an elongated source ofelectromagnetic energy at a wavelength in the range from about 700 to400 nanometers; means for mounting said source in the aperture in saidone wall of said housing; a transmission grating including a transparentmaterial having a height of not less than about 6 inches, an area notless than about 1 square foot and being ruled with not less than about6, 000 lines to the inch; and means for mounting said transmissiongrating at a distance not less than about 1 foot from the aperture insaid one wall whereby a plurality of observers may simultaneously viewspectral phenomena in the visible region.